In thick side of each chicken breast, cut 3-inch-long pocket to within 1/4 inch of opposite side of breast. For each breast, cut 1 slice of cheese in half, and add to pocket; cut 1 slice ham in half, and add to pocket. Secure with toothpicks. In small bowl, mix 1 tablespoon of the mustard, the Worcestershire sauce and smoked paprika. Brush chicken breasts with Dijon mixture.